<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>

      <!-- 所属分类 TODO -->
      <el-form-item label="课程分类">
        <!--一级分类-->
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级课程分类" @change="subjectLevelOneChanged">
          <el-option
            v-for="subject in oneSubjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        <!--二级分类-->
        <el-select
          v-model="courseInfo.subjectId"
          placeholder="二级课程分类">
          <el-option
            v-for="subject in twoSubjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>

      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select
          v-model="courseInfo.teacherId"
          placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>

      <!-- 课程简介 TODO -->
      <el-form-item label="课程简介">
          <tinymce :height="300" v-model="courseInfo.description"/>
      </el-form-item>

      <!-- 课程封面 TODO -->
      <el-form-item label="课程封面">
        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/eduoss/fileoss'"
          class="avatar-uploader">
          <img :src="courseInfo.cover">
        </el-upload>
        <p style="color:red">注意：1、上传图片格式须为jpg;&nbsp;&nbsp;2、图片大小不能超过2MB。
        </p>
      </el-form-item>
      
      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>

      <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
      </el-form-item>
    </el-form>
  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'//引入富文本编辑器组件
export default {
  //声明组件
  components:{Tinymce},
  data() {
    return {
      saveBtnDisabled: false, // 保存按钮是否禁用
      courseInfo: {
          title: '',
          subjectId: '',
          subjectParentId: '',
          teacherId: '',
          lessonNum: 0,
          description: '',
          cover: 'https://edu-llm01.oss-cn-beijing.aliyuncs.com/cover/bookFm.jpg',
          price: 0
      },
      courseId: '',
      BASE_API: process.env.BASE_API, // 接口API地址
      teacherList: [],
      oneSubjectList: [],
      twoSubjectList: []

    }
  },

  created() {
    if(this.$route.params && this.$route.params.id){
        this.courseId = this.$route.params.id
        this.getCourseInfo()
    }else{
      this.courseInfo = {
          title: '',
          subjectId: '',
          subjectParentId: '',
          teacherId: '',
          lessonNum: 0,
          description: '',
          cover: 'https://edu-llm01.oss-cn-beijing.aliyuncs.com/cover/bookFm.jpg',
          price: 0
      }
    }
    this.getListTeacher()
    this.getOneSubject()
  },

  methods: {
    //获取课程信息
    getCourseInfo(){
      course.getCourseInfo(this.courseId)
        .then(response => {
          this.courseInfo = response.data.courseInfoVo
            subject.getSubjectList()
              .then(response => {
                this.oneSubjectList = response.data.list
                for (var index = 0; index < this.oneSubjectList.length; index++) {
                  var oneSubject = this.oneSubjectList[index]
                  if(this.courseInfo.subjectParentId == oneSubject.id){
                    this.twoSubjectList = oneSubject.children
                  }
                  
                }
              })
        })
        this.getListTeacher()

    },
    //上传成功方法
    handleAvatarSuccess(res,file){
      this.courseInfo.cover = res.data.url

    },
    //上传前方法
    beforeAvatarUpload(file){
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2

      if (!isJPG) {
        this.$message.error('上传封面图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传封面图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M

    },
    //一级分类值改变，二级分类跟着改变
    subjectLevelOneChanged(value){//value等于一级分类的id
    for(let i=0;i<this.oneSubjectList.length;i++){
      if(this.oneSubjectList[i].id === value){
        this.twoSubjectList = this.oneSubjectList[i].children
        this.courseInfo.subjectId = ''
      }
    }
    },
    //查询所有一级课程分类
    getOneSubject(){
      subject.getSubjectList()
        .then(response => {
            this.oneSubjectList = response.data.list
        })
    },
    //查询所有讲师
    getListTeacher(){
      course.getListTeacher()
        .then(response => {
            this.teacherList = response.data.item
        })

    },
    //保存课程信息并下一步
    saveOrUpdate() {
      if(this.$route.params && this.$route.params.id){
        this.courseId = this.$route.params.id
        course.updateCourseInfo(this.courseInfo)
          .then(response => {
              this.$message({
                  type: 'success',
                  message: '修改课程信息成功'
              });
              this.$router.push({ path: '/course/chapter/'+this.courseId })
          })
      }else{
        course.addCourseInfo(this.courseInfo)
          .then(response => {
              this.$message({
                  type: 'success',
                  message: '添加课程信息成功'
              });
              this.$router.push({ path: '/course/chapter/'+response.data.courseId })
          })
      }
    }
  }
}
</script>
<style scoped>
  .tinymce-container {
    line-height: 29px;
  }
</style>